The present invention relates to motion stabilizers, and more particularly to devices including a spring and a telescoping body assembly for yieldingly holding a load in a normal or centered position.
There is a long standing need for a stabilizer for stabilizing the movement of a load that is movable relative to another load or a relatively fixed support. Such a stabilizer should yieldingly hold the load in a normal position. In may instances the normal position is a centered position in a range of movement of the load. The stabilizer should include a reaction unit having a spring acting through a body assembly to permit the load to be displaced from the normal position and to resiliently bias the load to return from the displaced position back toward the normal position.
There are numerous and varied applications for a motion stabilizer of this kind. One example of an application exhibiting such a need is the steering system of a large vehicle such as a truck or recreational vehicle. In this application, the motion stabilizer urges the steering gear toward a normal or centered position in which the vehicle travels straight ahead, and permits the steering gear to be displaced so that the vehicle can be turned. In a vehicle application, a motion stabilizer should be able to hold the vehicle under control in the presence of cross winds, road irregularities, tire blow outs and the like. Other applications for motion stabilizers include conveyors and manufacturing equipment, power boats, vehicles of many types and trailer hitch systems. A motion stabilizer can provide advantages in many situations where a movable load must be yielding held in a centered or normal position.
Many stabilizing or centering systems have been developed or proposed in the past. For example, U.S. Pat. Nos. 1,223,573 and 4,406,473 disclose vehicle steering stabilizer systems using a pair of coil springs urging a component of the vehicle steering linkage toward a centered or normal position. In another example, U.S. Pat. No. 4,822,012 discloses a bidirectional steering stabilizer having a single spring and a damper for yieldably biasing the wheels of a vehicle toward a straight ahead direction. Although these systems are relatively simple in that they are mechanical devices with relatively few parts, they suffer from disadvantages including interfering with the operator's ability to control the vehicle in a natural way, and a lack of the ability to accommodate a variety of types of springs and reaction units and the ability to easily adjust the stabilizer to match the requirements of a particular vehicle or application.
Another approach that has been used in the past is to provide a complex hydraulic and pneumatic system for assisting the power steering system of a large vehicle in holding the steering linkage and wheels on center. One example of a system of this type is the Howard Power Center Steering System sold by River City Products, Inc. of San Antonio, Tex. Although this steering control system performs well, it is subject to the disadvantages of complexity and large expense, and it is not easily adaptable to a variety of differing applications.